Galactic evolution. II. Why is the reddening law in our Galaxy unique? A working hypothesis.
Abstract
Based on calculations of the ratio of the force exerted by gravity and the force due to radiation pressure on spherical dielectric particles, it can be shown that dust grains of dimension greater than 0.000003 cm are retained by the Galaxy, while those smaller than that are repulsed. However, grains greater than 0.00003 cm are attracted by main sequence stars colder than A 5. Thus, only grains within the range from 0.000003 to 0.00003 cm can remain for a relatively long time in the Galaxy. This fact explains roughly why the reddening law in the Galaxy has always been found to be nearly the same, except in those particular regions where it reflects the circumstellar dust grain distribution rather than the interstellar distribution.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- September 1974
- Bibcode:
- 1974A&A....35....7P
- Keywords:
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- Cosmic Dust;
- Galactic Evolution;
- Gravitational Effects;
- Interstellar Matter;
- Radiation Pressure;
- Main Sequence Stars;
- Particle Size Distribution;
- Radiation Effects;
- Astrophysics